Petroleum refiners produce desirable products, such as gasoline and turbine fuel, by catalytically hydrocracking high boiling hydrocarbons into product hydrocarbons of lower average molecular weight and boiling point. Hydrocracking is generally accomplished by contacting, in an appropriate reactor vessel, a gas oil or other hydrocarbon feedstock with molecular hydrogen in the presence of a suitable hydrocracking catalyst under appropriate conditions, including an elevated temperature and an elevated pressure, such that a hydrocarbon product is obtained containing a substantial proportion of a desired product boiling in a specified range.
Often, hydrocracking is carried out in the presence of a catalyst containing sulfided Ni--W or Ni--Mo metals. However, these catalysts produce a substantial amount of aromatic content. In some application, such as for jet fuel and diesel as such or as a blend a lower amount of aromatic content is desired.
In order to obtain a lower aromatic content hydrocracked product, noble metal hydrocracking catalyst is being used. However, the conventional noble metal catalysts have a substantial gas make (C.sub.1 to C.sub.4), thus lowering the desired liquid yield, i.e., within the range of from C.sub.5 to hydrocarbons boiling at about 650.degree. F.
It is desirable to provide a noble metal hydrocracking catalyst which will produce less gas and more liquid products under hydrocracking conditions.